EP2837531A1

EP2837531A1 - Single panel airbag module

Info

Publication number: EP2837531A1
Application number: EP13004025.6A
Authority: EP
Inventors: Fernando José Eireos Garcia
Original assignee: Dalphi Metal Espana SA
Current assignee: Dalphi Metal Espana SA
Priority date: 2013-08-13
Filing date: 2013-08-13
Publication date: 2015-02-18
Anticipated expiration: 2033-08-13
Also published as: EP2837531B1

Abstract

The invention refers to a method of forming an airbag module and to an airbag module comprising an inflatable air bag folded from a single panel, and retaining means for attaching the airbag to a portion of an airbag module housing.

For providing an improved airbag for an airbag module in which the thermal and mechanical properties are significantly improved exactly in the areas where these requirements are higher, without complicating the construction of the bag, it is suggested that the air bag comprises a plurality of holes located in a perimeter region of the single panel wherein at least one of or one portion of the retaining means passes through at least two of the holes.

Description

The invention refers to a method of forming an airbag module and to an airbag module comprising an inflatable air bag folded from a single panel, and retaining means for attaching the airbag to a portion of an airbag module housing.
Conventionally, an airbag module basically consists in a folded bag that inflates quickly through gas produced by a generator when certain sensor devices detect a vehicle collision. This way the bag unfolds between the vehicle occupant and a part of the vehicle, protecting the occupant during a collision.
Typically, bags for airbags are made from two main fabric panels that are sewed together by a peripheral stitch in order to form the inflatable bag of the airbag module. Furthermore, in the bag areas where the thermal and mechanical requirements are higher, these bags comprise additional fabric layers that are intended to reinforce the mentioned areas.
These known solutions of multi-panel airbag modules have the disadvantage that several layers or panels have to be sewed or stitched together in order to form the inflatable bag of the airbag module, which leads to the existence of gas leakage through the peripheral stitches once the bag is inflated. The mentioned leakages make that the adjustment of the permeability of the bag is very complicated, which leads to more tests being necessary during manufacturing of the module and to higher fabrication costs. Moreover, in the bag areas where the thermal and mechanical requirements are higher, these bags must be provided with additionally stitched fabric layers in order to reinforce these areas, which obviously make the manufacturing of the bag more costly, time-consuming and complicated.
Besides, US 5,087,071 discloses an air bag module of the above kind wherein the air bag is formed by a single piece of fabric. Herein, the fabric is folded, with its end portions partially overlapping the central portion, and the edges being joined together by seams to form an inflatable airbag. However, like in conventional air bags, the disadvantage of such an airbag module remains that the gas leakage through the stitches is still a fact. Besides, the stitching operations needed make the manufacturing process costly and complicated.
An objective of the present invention is to provide a bag for an airbag module having a simplified construction, requiring fewer parts and fewer operations, such as stitching, in order to manufacture the inflatable bag.
Another objective is to provide a bag for an airbag module in which the thermal and mechanical properties are significantly improved exactly in the areas where these requirements are higher, without complicating the construction of the bag.
Still another objective of the present invention is to reduce dramatically or to completely avoid gas leakages to the outside of the bag, in order to increase the bag performance.
According to a method aspect of the invention, these and other objectives are achieved by a method of forming an airbag module, comprising the steps of: providing a single panel with a plurality of holes in a perimeter region of the panel; folding a sector of the panel on another sector of the panel, thereby aligning at least a first one of the holes with at least a second one of the holes, and inserting retaining means into the aligned holes of the airbag.
Alternatively or additionally, these and other objectives are achieved by a method of forming an airbag module which comprises the step of providing a single panel having a perimeter region and a step of forming an inflatable air bag structure solely by pressing portions of the perimeter region onto adjoining portions of the perimeter region during a step of fixing the inflatable air bag structure to a portion of an air bag module housing, in particular together with a gas inflator, preferably by means of nuts and bolts.
Preferably, in such methods of forming an airbag module the step of folding is repeated for remaining sectors of the surface of the panel.
Further preferably, such methods of forming an airbag module comprise a step of temporarily fixing the alignment of the holes by inserting attaching elements, in particular bolts, into the holes.
Also, preferably, such methods of forming an airbag module comprise a step of removing the attaching elements prior to inserting the retaining means into the aligned holes.
Even further preferably, such methods of forming an airbag module comprise a step of attaching a gas inflator to the retaining means, in particular by means of nuts being screwed to the retaining means.
Also, further preferably, such methods of forming an airbag module comprise a step of fixing the air bag to a portion of an airbag module housing, in particular by means inserting the retaining means into holes provided in said an airbag module housing and/or by means of nuts being screwed to the retaining means.
For an airbag module of the above kind, these and other objectives are achieved in that the air bag comprises a plurality of holes located in a perimeter region of the single panel wherein at least one of or one portion of the retaining means passes through at least two of the holes.
Also, these and other objectives are achieved for an airbag module of the above kind in that the air bag is folded and from the panel into an inflatable structure free from any kind of stitching or gluing and retained as such inflatable structure by being sandwiched at the perimeter region of the single panel between the retaining means and the portion of the airbag module housing.
As already explained, with the bag of the invention, no peripheral stitching is needed in order to join the main panel, as the bag of the invention is made from just one panel. Thus, the manufacturing of such bag is simpler and more cost-effective.
Besides, thermal and mechanical properties of the airbag module are significantly increased, without any additional step and without complicating the construction of the bag, because the airbag module of the invention comprises additional folding where the thermal and mechanical requirements in the bag are higher, without any stitching being needed. Thus, in the own construction of the bag, these thermal and mechanical properties are increased only in the areas needed.
Preferably, in such an airbag module, the panel is folded in four sectors of one quarter of the surface of the panel.
It is further preferred, that the airbag comprises additional reinforcing folding in the areas of the airbag that are located adjacent to the retaining means and/ or to a gas inflator being part of or being held by the retaining means.
It is also preferred, that the retaining means comprises at least one, preferably two, further preferably three, most preferably four, or more attachment bolts, configured to pass through holes provided in the airbag and/ or in the airbag module housing.
According to one embodiment, the retaining means is formed by a flange of the inflator.
According to another embodiment, the retaining means is formed to secure the inflator at its flange to the module housing, preferably ring shaped to circumcise a central diffuser section of the inflator.
Preferably, the retaining means comprises plural, preferably four attachment bolts, each bolt passing through the same number of holes provided in the airbag. Thereby the airbag has a symmetrical shape and even forces acting on all parts of the attached portions thereof.
Hereinafter the invention will be explained in greater detail with further features, characteristics, and advantages with reference to the attached figures, wherein:

Figure 1 shows the single panel that is going to form the bag of the airbag module according to the invention,
Figures 2a and 2b show the step of folding a sector in a method of forming a bag for an airbag module according to the invention,
Figure 3 shows the appearance of the bag once the sectors of the panel bag have been folded, in the method of forming a bag for an airbag module according to the invention,
Figure 4 shows an alternative of the method of forming a bag for an airbag module according to the invention,
Figure 5 shows a view inside out of the final shape of the bag for an airbag module according to the invention,
Figure 6 shows a view of the final shape of the bag for an airbag module according to the invention,
Figures 7a, 7b, 7c and 7d show the step of introducing the retaining means inside the bag in the method of forming a bag for an airbag module according to the invention,
Figures 8a and 8b show the step of placing the gas inflator in the method of forming a bag for an airbag module according to the invention, and
Figure 9 shows a general view of the bag of the airbag module according to the invention, once it is deployed.

In a first aspect, the invention discloses a bag 1 for an airbag module used in vehicles, the bag 1 being formed from a single fabric panel 2 comprising a plurality of holes 3 located in the perimeter of the fabric panel 2 making the bag 1. By folding the panel 2 and retaining this folding by means of retaining means 4, the bag 1 is tailored and shaped without the need of any stitching. Thus, the bag 1 comprises a plurality of holes 3 located in the perimeter of the panel 2 and retaining means 4, such that the panel 2 is folded in sectors, for example in sectors or segments 7, 8, 9 and 10 of each one quarter of the surface of the panel 2 (see Figure 6) by way of the holes 3 being brought together and being retained by the retaining means 4, in order to tailor and shape the bag 1.
With the bag 1 of the invention, no peripheral stitching is needed in order to join the main panel 2, as the bag 1 is made from just one panel 2. Thus, the manufacturing of said bag 1 is simpler and more cost-effective. Initially, the folding in the bag 1 is retained by temporary attaching elements 6, which are removed once the bag 1 is fixed to the retaining means 4. The attaching elements 6 are preferably screws.
Besides, thermal and mechanical properties of the airbag module are significantly increased, because the bag 1 comprises additional folding (not shown) where the thermal and mechanical requirements in the bag 1 are higher, namely about the inflator.
In Figure 4, the shape of the folded bag is shown. As can be seen multiple folding in the periphery area of the panel is given by overlapping adjacent or distant sections of the bag which are to be held by the retaining means at assembly of the module.
As shown in Figure 9, an airbag 1 made following the invention is deployed to a shape similar to a multi-piece panel bag. As in such traditional bags, one or more venting holes, that can regulate the bag pressure, can be provided at a suitable position.
The main advantages obtained by the bag 1 of the invention are: product simplification, product line simplification, cost savings, improved thermal and mechanical performance where more needed and gas leakage dramatically reduced.
Although several embodiments of the invention have been described and represented, modifications can be made within its scope, and therefore should not be considered as limited to these executions, but the content of the following claims.

Claims

Method of forming an airbag module, characterized by the steps of:
• providing a single panel (2) with a plurality of holes (3) in a perimeter region of the panel (2);

• folding a sector (7) of the panel (2) on another sector (7) of the panel, thereby aligning at least a first one of the holes (3) with at least a second one of the holes, and

• inserting retaining means (4) into the aligned holes (3) of the airbag (1).
Method of forming an airbag module according to claim 1, characterized by repeating step b) for remaining sectors of the surface of the panel (2).
Method of forming an airbag module according to claim 1 or 2, characterized by a step of temporarily fixing the alignment of the holes (3) by inserting attaching elements (6), in particular bolts, into the holes (3).
Method of forming an airbag module according to claim 3 characterized by a step of removing the attaching elements (6) prior to inserting the retaining means (4) into the aligned holes (3).
Method of forming an airbag module according to any of claims 1 to 4, characterized by a step of attaching a gas inflator to the retaining means (4), in particular by means of nuts (12) being screwed to the retaining means (4).
Method of forming an airbag module according to any of claims 1 to 5, characterized by a step of fixing the air bag (1) to a portion of an air bag module housing (11), in particular by means inserting the retaining means (4) into holes provided in said an air bag module housing (11) and/or by means of nuts (12) being screwed to the retaining means (4).
Method of forming an airbag module, preferably according to any of claims 1 to 6, characterized by providing a single panel (2) with a perimeter region and a step of forming an inflatable air bag structure (1) solely by pressing portions of the perimeter region onto adjoining portions of the perimeter region during a step of fixing the inflatable air bag structure (1) to a portion of an air bag module housing (11), in particular together with a gas inflator, preferably by means of nuts (12) and bolts (4).
An airbag module for a vehicle, preferably formed by a method according to at least one of the previous claims 1 to 7, the air bag module comprising an inflatable air bag (1) folded from a single panel (2), and retaining means (4) for attaching the airbag (1) to a portion of an airbag module housing (11), characterized in that the air bag (1) comprises a plurality of holes (3) located in a perimeter region of the single panel (2) wherein at least one of or one portion of the retaining means (4) passes through at least two of the holes (3).
An airbag module for a vehicle according to the preamble of claim 8, characterized in that the air bag (1) is folded and from the panel (2) in an inflatable structure free from any kind of stitching or gluing and retained as such inflatable structure by being sandwiched at the perimeter region of the single panel (2) between the retaining means (4) and the portion of the airbag module housing (11).
Airbag module according to claim 8 or 9, characterized in that the panel (2) is folded in four sectors (7, 8, 9, 10) of one quarter of the surface of the panel (2).
Airbag module according to any of the claims 8 to 10, characterized in that the airbag (1) comprises additional reinforcing folding in the areas of the airbag (1) that are located adjacent to the retaining means (4) and/ or to a gas inflator being part of or being held by the retaining means (4).
Airbag module according to any of the claims 8 to 11, characterized in that the retaining means (4) comprises at least one, preferably two, further preferably 3, most preferably 4, or more attachment bolts, configured to pass through holes (3) provided in the airbag (1) and/ or
in the airbag module housing (11).
Airbag module according to any of the claims 8 to 12, characterized in that the retaining means (4) is formed by a flange of the inflator.
Airbag module according to any of the claims 8 to 12, characterized in that the retaining means (4) is formed to secure the inflator at its flange to the module housing.
Airbag module according to any of the claims 8 to 14, characterized in that the retaining means (4) comprises plural, preferably four attachment bolts, each bolt passing through the same number of holes (3) provided in the airbag (1).